Wuchereria bancrofti, the major causative organism of lymphatic filariasis (LF), is a filarial nematode estimated to infect 120 million people worldwide, with an additional billion people felt to be at risk for infection. Wuchereria bancrofti is a vector-borne parasite that has a complex lifecycle that begins when the infective larvae stage (L3) are deposited on the skin. These L3 develop in the human (over a six month period) to adults living in lymphatics where they mate and produce microfilariae that circulate in the blood and which ultimately get picked up by new vectors to complete the lifecycle. The period between infection and when the microfilariae appear is called the prepatent period and it is during this period when standard diagnostics are not useful.
Among the neglected tropical diseases (NTDs), lymphatic filariasis is one that has been targeted for elimination by 2020 using mass drug administration (MDA) to interrupt transmission of this mosquito borne infection. As part of this effort, based on yearly administration of two antifilarial drugs, methods for detecting infection during the prepatent period is necessary both to detect infection on an individual basis and to detect early recrudescence once MDA is instituted. Moreover, methods to be used to certify areas free of infection will also be necessary. To date, the antigens used to base assays, such as Bm-14, have suffered from complete cross-reaction with Brugia malayi (a related filarial parasite) and also from significant cross-reaction with other filarial parasites such as Loa loa, Mansonella perstans, and Onchocerca volvulus (the causative agent of onchocerciasis), whose geographic distribution often overlaps with that of Wuchereria bancrofti. Thus, given the potential for the serious, disabling disease associated with Wuchereria bancrofti and Brugia malayi infection, there is a need both to detect infection early following exposure to infective mosquitoes, and to certify areas free from infection, there remains a need for new methods of diagnosis to detect Wuchereria bancrofti and Brugia malayi. 